Clock



Oct; 20, 1942. WHITEHEAD 2,299,519

CLOCK Filed July 18, 1940 Patented Oct. 20, 1942 CLOCK Richard H.Whitehead, New Haven, Conn., as-

signor to The New Haven Clock Company, New Haven, (John, a corporationof Connecticut Application July 18, 1940, Serial No. 346,070

6 Claims.

This invention relates to instruments of the type having gears pivotedin supporting frames which are here typically represented by and referred to as clocks and more particularly to a construction whichaffords bearings of a superior hardness.

In the construction of watches, clocks, electrical instruments and otherinstruments involving gears it has been customary to mount the gears inspaced plates, which plates are usually made of brass to secure themfrom corrosion. These plates must have provided in them the bearings forthe pivots of the gears.

Heretofore it has been customary, in the cheaper watches, to journal thegears in holes in the plates so that the pivots themselves have directbearing against the material of the plate. This material beingnecessarily soft enough to be subjected to mechanical operations, isliable to wear and at the same time, in spite of all precautions, it hasa certain degree of friction which is detrimental to the operation ofthe instrument.

To overcome these difiiculties it has been customary in the higher gradewatches to drill the holes for the bearings large enough to receive ajewel of ruby, sapphire or some synthetic material, which jewel isitself pierced with a polished hole to serve as a bearing for the pivot.This construction produces good results but is quite expensive bothbecause of the cost of the material and the labor of cuttin polishingand inserting them. A watch having such jewels is better time p r andhas a longer life than a watch in which the pivots bear directly in theplate as heretofore constructed, but the high cost places thisconstruction beyond the cheaper watch.

It is an object of this invention to provide a watch in which the platesare made 'of an aluminum metal, such as aluminum or a suitable aluminumalloy, having the pivot bearing holes punched, drilled or out directlytherein and then to subject the plate to certain hardening processeswhich convert the aluminum to one of its very hard compounds, forexample as shown by Patents No. 2,153,060; 1,946,147; 2,040,617;2,040,618; 1,891,703; 2,108,603; 2,108,604; and 2,084,327. Thistreatment is a surface treatment which is capable of giving greathardness to the surface of the material while leaving the inner layerstough. Thus, we have in this invention the ideal combination of a veryhard bearing surface at the point where the plate is in contact with thepivot while at numeral .ll designates the back plate.

the same time we have the tough supporting plate clear up to andintegral with that bearing surface so that there is no reasonable strainto which the instrument can be subjected which could crack the bearingsurface.

The invention accordingly comprises an article of manufacture possessingthe features, properties and the relation of elements which will beexemplified in the article hereinafter described and the scope of theapplication of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description, taken inconnection with the accompanying drawing, in which:

Fig. 1 is a plan view of a watch movement embodying this invention,illustrating particular.

ly the type of movement used in the ordinary so-called Dollar watch.

Fig. 2 is a side elevation of a watch movement such as is shown in Fig,1.

Fig. 3 is a view similar to Fig. 1 showing a modified form of thestructure.

' Fig. 4 is a further modification.

It will be understood that so far as the arrangement of the gears andpivots or the shape of the plates shown in these views, they form nopart of the present invention and any type of instrument or any shapeplate convenient to the type of instrument chosen may be employed.

-As illustrated in Fig. 1 the numeral l0 designates the front plate of awatch movement designed to support or underlie the face and the 0 Thesetwo being held in spaced relation in any customary manner. As shown,there is provided a main spring I! which, through the means of anyconvenient gear train, herein illustrated as gears l3 and I4, drives theminute shaft I5 in the customary manner.

Each of the plates l0 and II in the modification shown in Fig. 1 isdrilled or punched with suitable holes, here indicated generically withthe numeral l6, which holes serve as the pivot holes for certain or allof the pivots of the gears.

As shown in Fig. 1 the back plate carries all of the pivots except thepivot H for the balance wheel l8 and the back pivot IQ for the mainspring l2. The balance wheel pivot is carried in a suitable screw l1 andthe main spring pivot I9 is carried in an auxiliary plate 20, as shown.Each of these plates l0 and 2.0, in accordance with this invention, ismade with an aluminum metal, that is either pure aluminum or an alloy 2v of aluminum containing a sumciently high percentage of aluminum to besubject to the surface hardening processes which are characteristic ofaluminum.

The manufacture of these cheaper watches must necessarily be kept on aquantity production 'of one of the aluminum compounds having asufficient alloy to render it free cutting and to maintain itsstiffness.-

The punching operation is carried with punches of substantially thediameter of the finished bearings, except for the very small train holeswhich are prick punched and shaved to size. After the plate iscompletelypunched and preferably after all mechanical operations upon it arecompleted, it is subjected to a mechanical surface hardening processwhich converts the film surface to one of the very hardened aluminousmaterials. This treatment is conducted in such a manner that the surfaceconversion occurs particularly throughout the cylindrical surface of thebearing holes but it is desirable that it be conductedin such a mannerthat only the film surface is treated since a more satisfactory bearingis provided if the hardened surface is immediately surrounded by thetough unhardened metal to resist any tendency to crack or chip.

Ordinarily the process of surface hardening if applied to a surfacealready polished will produce a polished surfac after hardening.Subsequent further polishing may, however, be performed if desired.

If the particular process of hardening alters the size of the bearing orif the size is to be altered by subsequent polishing, that fact will betaken into account in determining the diameter of the punching dies.

The construction of Fig. i is intended toillustrate a plate made inaccordance with this in-' vention in which the whole of the supportingplates III, II and 20 is subjected to the surface hardening process sothat .there is a hardening over the fiat surface of the plate as well asat the bearing surfaces. This embodiment of the invention possesses thegreat advantage that it may be accomplished with a minimum of specialat- V tention.

In utilizing this form of the invention, however,

. care must be taken to see that the hardening pen- -etrates down intothe bearing surfaces.

fl'he form of the invention shown in Fig. 3 is i fntical with that shownin Fig. 1 except that this figure illustrates a modification in whichthe surface hardening is confined to the areas im- 'mjediatelysurrounding the bearing surfaces.

is illustrated by the circles 25, which surround the bearings i8 and I9. It will be understood that ordinarily there is i no difference inappearance between this metal when surface hardened and the unhardenedportion' of the materialso that the placing of this the surfacehardening has spread on the surface circle 25 upon theportlon is, tothis extent, diagrammatic rather than an illustration of theactualappearance of the finished plate. This circle is intended toindicate the area over which of the plate but it will be understood thatin most cases there will be no such hard and sharp lines of division asthis circle seems to indicate.

This form of the invention has the merit that it leaves the body of theplate unhardened so that it may be easily subjected to any furtheroperations such as polishing, embossing or engraving to which it may bedesired to subject it.

It also possesses the merit when expensive processes are used that thearea to be processed is reduced to a minimum.

Where processes are employed which rely pon electrical phenomena, it ispossible to secure penetration of the hardening process into the bearingsurfaces by providing electrodes capable of passing into these bearingsurfaces and where such localization of electrical action is desired, itmay. in many instances, be found helpful to provide a local surfacehardening at the bearing surfaces rather than to attempt to subject thplate to a surface hardening all over, since the latter is apt toconcentrate too much upon the flat surfaces without sufiicientpenetration intothe bearings.

Fig. 4 illustrates the invention as applied to the higher grade movementwhich is ordinarily of the jeweled type. In such case a plurality ofbackplates 30 and II are provided, each of which carries on or more of thebearings and each of these plates is hardened at the bearings, either asdisclosed in Fig. l or Fig. 3, and for this reason no separable orseparate jewels are required.

The pivot I I for the balance stafl may be made in any convenient form,for example the hardened steel screws now customarily used for cheaperwatches may be utilized but I prefer to fabricate a part of a screw ofaluminum metal having the desired form of bearing surface and thensurface harden it as in the case of the supporting plates, so that thebalance wheel also may have the benefit of the superior qualities of thesurface hardened aluminum. This is particularly important in the case ofthe higher grade watches where the new construction is to take the placeof the balance wheel jewels.

A watch made in accordance with this invention has all the advantages ofa jeweled movement in that it has long life, low friction, and accuracy,at the same time it possesses the advantages of a constructionheretofore confined to the cheap watch field, namely plate pivots, sothat the advantage of hardened bearings may be carried into the cheapwatch fleld.

It will also be noted that the watch made in accordance with thisinvention carries all of the advantages of the high grade jeweledmovement without one of the serious limitations to which such movementsare subjected, namely with this construction there is no liability of ajewel being cracked, chipped or broken since the hardened bearingsurface is immediately surrounded by the more ductile and tougherunhardened material of the plate.

1 Since certain changes may be made in the above construction anddifferent embodiments of the invention could be made without departingfrom the scope thereof. it is intended that all matter contained in theabove description or invention which, as a matter of language, might besaid to fall therebetween.

Having described my invention, what I claim as new and desire to secureby Letters Patent, is: 1'. An instrument of the type having the pivotsof a gear train mounted in bearing supporting plates, having thesupporting plates made of an aluminum metal, said aluminum beingchemically surface hardened over the surface of the bearing holes in thepiece at the bearing surfaces, whereby there is provided a bearingsurface comparable or superior to the customary jeweled bearings, saidbearing surface being immediately surrounded by the tough unhardenedmaterial integral with it.

2. An instrument of the type having the pivots plates, having thesupporting plates made of an aluminum metal, said aluminum beingchemically surface hardened all over, including the "surface of thebearing holes, whereby there is provided a bearing surface comparableorsuperior to the customary jeweled bearings, said 3. An instrument ofthe type having the pivots of a gear train mounted in bearing supportingplates, having the supporting plates made of an r of a gear trainmounted in bearing supporting gear pivots therein, said bearings beingchem-' ically surface hardened over their entire hearing surfaces,whereby there is provided a plate having hardened bearing surfacesintegral with and firmly supported by the tough metal of the plate.

5. The process of making a supporting plate for an instrument whichcomprises forming the plate of an aluminum metal with openings thereinsuitable for bearings and then chemically surface hardening the platethroughout the bearing areas to leave a thin hardened surfaceimmediately supported by the unhardenedmetal of the plate.

6. An instrument comprising a frame, bearings in said frame, gearspivoted in said bearings, said frame being of aluminum and the surfacesof said bearings being of chemically hardened aluminum integral withsaid frame.

RICHARD H. WHI'I'EHEAD.

